SoFunction
Updated on 2025-03-02

Various methods to implement data crawling in Python

Preface

JavaScript is a powerful scripting language that is widely used in front-end development of web pages, building interactive user interfaces, and handling various client-side tasks. However, sometimes it may be necessary to execute JavaScript code in a Python environment, whether to interact with web pages, automate browser operations, or perform tasks that require JavaScript.

This article will introduce a variety of ways to help you execute JavaScript code in Python and provide detailed sample code to make this skill easy.

1. Why JavaScript needs to be executed in Python

There are a number of situations where JavaScript code is executed in Python, some of which include:

  • Web automation:By executing JavaScript, users can simulate interactions on web pages, such as clicking buttons, filling in forms, etc., thereby automating web browser operations.
  • Web data crawling:Some websites use JavaScript to generate content dynamically. By executing JavaScript in Python, these dynamically generated data can be obtained.
  • Front-end development:Front-end code can be tested in a Python environment to ensure it works correctly with the back-end service.
  • Web Application Integration:Integrate the Python backend with the JavaScript frontend to build more complex web applications.

2. Execute JavaScript using the Python built-in library execjs

execjsIs a built-in library for Python that allows execution of JavaScript code. This approach is suitable for executing simple JavaScript code without the need for a browser environment.

Install execjs

First, install execjs.

Use pip to execute the following command:

pip install PyExecJS

Execute JavaScript code

Here is an example of executing JavaScript code using execjs:

import execjs

# Create a JavaScript contextctx = ("""
function add(x, y) {
    return x + y;
}
""")

# Execute JavaScript functions in contextresult = ("add", 3, 4)
print(result)

In this example, a JavaScript context is created using execjs, and the JavaScript function is executed in that context. Any JavaScript code can be executed in the context.

3. Execute JavaScript using PyExecJS

PyExecJSis another Python library for executing JavaScript code, providing similar functionality to execjs.

Install PyExecJS

Install PyExecJS using pip:

pip install PyExecJS

Execute JavaScript code

Here is an example of executing JavaScript code using PyExecJS:

import PyExecJS

# Create a PyExecJS contextctx = ("""
function multiply(x, y) {
    return x * y;
}
""")

# Execute JavaScript functions in contextresult = ("multiply", 3, 4)
print(result)

In this example, a JavaScript context is created using PyExecJS, and the JavaScript function is executed in that context. This is similar to using execjs.

4. Execute JavaScript with Selenium and WebDriver

SeleniumIt is a tool for automating browser operations, which can be used with different browsers, including Chrome, Firefox, Edge, etc. Through Selenium and browser drivers (such as ChromeDriver, GeckoDriver), JavaScript code can be executed and interact with page elements.

Install Selenium

First, install Selenium. Use pip to execute the following command:

pip install selenium

Then, you need to download the WebDriver for the browser you are using. For example, if you use Chrome browser, you need to downloadChromeDriver。

Execute JavaScript code

Here is an example of executing JavaScript code using Selenium:

from selenium import webdriver

# Initialize Chrome browser driverdriver = (executable_path='/path/to/chromedriver')

# Open the web page('')

# Execute JavaScript coderesult = driver.execute_script('return 3 + 4;')
print(result)

# Close the browser()

In this example, the Chrome browser driver is first initialized and a web page is opened. Next, usedriver.execute_scriptThe method executes the JavaScript code and finally closes the browser.

5. Execute JavaScript using

It is a JavaScript runtime based on the Chrome V8 engine, allowing JavaScript code to be run on the server side. You can use , to execute JavaScript scripts and to call processes from Python.

Install

First, install . CanOfficial websiteDownload and install .

Create JavaScript Files

Create a JavaScript file, e.g.my_script.js, which contains the JavaScript code you want to execute.

Here is an example:

// my_script.js

function add(x, y) {
    return x + y;
}

add(3, 4);

Execute JavaScript code

Here is an example of executing JavaScript code using Python calls:

import subprocess

# Execute the process and run the JavaScript fileresult = subprocess.check_output(['node', 'my_script.js'], text=True)
print(result)

In this example, using Python'ssubprocessThe module starts a process and runsmy_script.jsJavaScript code in the file.

6. Choose the right method

The way to choose to execute JavaScript code in Python depends on your needs and usage:

  • If you just need to execute some simple JavaScript code without the browser environment, useexecjsorPyExecJSIt is a lightweight method.
  • Selenium and WebDriver are the only choice if you need to interact with web pages or automate browser operations.
  • If you want to run JavaScript code on the server side and call it from Python, it is the best option.

Choose the right method according to the project needs.

Summarize

Executing JavaScript code in Python can help with a variety of tasks, including web automation, data crawling, front-end development, and web application integration.

This article describes a variety of methods, including using built-in librariesexecjsandPyExecJS, Selenium and WebDriver, and calling processes. Depending on the specific needs and usage, selecting the appropriate method can execute JavaScript code more efficiently, thereby achieving more functions.

The above is the detailed content of various methods for executing JavaScript in Python to implement data crawling. For more information about executing JavaScript in Python, please pay attention to my other related articles!